Insert for rock drilling bits



FIG. 1 is a bottom view of an insert for rock drilling bits showing our new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a left side view thereof; and,

FIG. 4 is a top view thereof showing the cutting tip.

The other two sides are not shown as they are identical to the right and left sides as shown. 

The ornamental design for insert for rock drilling bits, as shown and described. 